Recording apparatus



June 17, 1941. 'r. A. RICH RECORDING APPARATUS Original Filed Nov. 26, 1938 Inventor": Theodore A.Ric h, %m dajw@ 9 His Attorney.

R www Patented June 17, 1941 RECORDING APPARATUS Theodore A. Rich, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Original application November 26, 1-938; Serial No.

242,543.- Divided and this application December 4', 1939, Serial No. 307,549

1 Claim. (01. err-2.6)

This application is a division of my applican 8- N. 2 ,5 filed November 26, 1938 on an impulse measuring and recording. apparatus,

said parent application containing, claims directed primarily to the subject. matter of the novel galvanometer described herein. The present application contains claims directed to features for maintaining the recording chart straight as it is advanced. Another divisional applicatiomJSerial No. 269,805, filed vAprll 24, 1939 contains claims directed to the novel timing control .of the galvanometer recorder. Another divisional application, Serial No. 269,806, filed April 24, 1939 contains claims directed to a novel means for stopping advance of the recording chart when recordin operations cease. Another divisional application is being filed concurrently herewith containing claims directed to the features of printing spaced calibration marks on the record sheet. when a record is made.

The features of my invention which are believed to be novel andpatentable will be pointcd out in the claim appended hereto. "For a better understanding of my invention reference is made in the following description to the accompanying drawing in which Fig. 1 represents a perspective view of a recording ga'lvanometer embodying my invention and Fig. 2 shows an enlarged view of a portion of the chart-straightening roller embodying my invention.

The galvanometer comprises essentially three parts, first a measuring element energized by coil l3, and having a two-pole stationary magnet 14 and a two-pole magnetic armature 15 secured to the rotary shaft l6; second, a damping element consisting of a disk. I! of conducting material secured to shaft l6 and one or more stat onary permanent magnets 18 which convey a damping flux through the disk 11 for damping purposes; and third, a zero return element consisting of a two-pole magnetic vane is secured to shaft l6 and a two-pole stationary field magnet 20 which when energized tends "to turn its vane I 9 into alignment with its pole :pieces at approx1mate1y the zero position of the shaft 18. A recording arm 2! is secured to shaft Ii, and

its outer end extends freely between a record sheet 22 and a printing :rod 23.-

The record printing apparatus may comprise a printing platten 24 in the form of aroller beneath the printing rod 23. About drum 24 3st.

belt 25 of carbon paper or its equivalent. The

record sheet 2 2 is preferably suiflcient-ly thin as to be transparent so that when the printing rod 23 forces pointer 2| down .againstrthe printing platten with the record sheet and carbon paper intervening, a mark is made on theunder surface of the record. sheet of the position of pointer 2 l', which mark is visible through the transparent sheet. 25 represents a supply roll for the record sheet. and 28 a driving drum for the record sheet. 29 is a small timing motor used for driving the drum Zlfor advancing the chart 22. The advance of chart 22 rotates roller 24 and since the carbon paper belt 25 is about roller 24 in contact with chart 22 the carbon paper belt 25 is also advanced by motor 29. The carbon paper belt 25 is advanced over roller 24 at about the same rate as the record sheet is advanced above it, but, except during the instance of printing, the carbon paper does not transfer marking material to the record sheet.

In order automatically to stop the advance of the record sheet when welding operations ,are temporarily discontinued, I have provided a special. contact device for opening the circuit of the timing motor 29. The contacts of this device comprise a metal wheel 3| and a resilient metal brush 32 bearing against the wheel 3i and included in the circuit of motor 29.

As here shown. the metal wheel 3| is urged in a counter-clockwise direction by a light spiral spring 33 and has an insulating finger 34 extendingfi'om its periphery which, if rotated clockwise against the upper end of contact 32, forces the contact away from wheel St to open the circuit of the timing motor 29. This contact mechanism is pivotally mounted at 21 and is connected with the armature 35 of a relay 35 by rod 30.

This relay 36 is energized following the occur- It is seen that in a short time interval, if the relay 35 is not energized, insulating finger 34 *wil-lrotate against spring finger 32 and move it away from wiheel 3] to break the timing motor circuit.

This condition of affairs will remain until relay it is energized. When this happens the contact assembly is swung to the right about pivot '21 and the gears at 28c are separated. Now

' spring 83, which has been wound up, can rotate ll counter-clockwise until finger 34 is stopped by contact with a stop a. Finger 32 is now in contact with wheel 3| and the timing motor starts in operation to advance the record sheet.

Ordinarily when surges to be recorded are coming in at a rate of say once per second, the fin get 24 does not reach contact 32 but is repeated;

1 ly returned against its stop and the'timing motor circuit remains energized to advance the record sheet continuously, but as soon as relay 36 remains deenersized for a somewhat. longer pe-.

riod. which period may be made anything desired,

"audible'signal 61, a controlrelay 38, as well as a source of supply 69. The relay 68 may be arranged to shut oil the power supply to the welder so that no further use thereof may proceed until the timing motor circuit is again opened and remains open until the next surge to be recorded occurs. It will be evident that with this arrangement the record sheet will always be advanced so as to leave a clean portion of the .record sheet in recording position when the motor stops and hence the first impulse that comes in and.

starts-the timing motor will be properly recorded.

This expedient. not only saves considerable recording and carbon paper, but itsaves wear and tear on the recording apparatus .and. useless operation of the timing motor. K Delays incident to renewing the recording paper supply are -re duced, and the records which are obtained are condensed and easier to study-than .if scattered over an unnecessary length of-record sheet.

The printing rod 23- extends overthe recording swing of pointer-1i and may be resiliently suspended and provided with a magnet which will be momentarily energized atthe prcperitime, as hereinafter explained, to perform; a. recording operation. Y

The nature of, by the dotsindicated at on record sheet 22. As illustrated, the printing rod 23 is provided with -a removable; or adjustablesection 6| of insulatins material-such 'asrubber. At the lateral boundaries of thisinsulatedrsection there are the printing relay .3! is'energized, print boundary the apparatus has been checked and the conditioncorrected. When the pointer is opposite the insulated part 6| when the record is printed the lower edge of the insulated part strikes the pointer and hence-the signal or control circuit lines I! on the record'sheet22 when the records II are printed.

The front section M of the .printingrod which holds rubber part 81 and the boundary printing ridges 82-. is either removable or adiustable.- In

the example shownfl'the adjustable part 64 is fastened to the main part 23 of the printing rod by screws ll. when these screws are removed. part I! with insulating part GI and the boundary printing ridgesmay be moved laterally or removed entirely and replaced by another section N having the insulated part 6| wider or nar-'- rower than the part SI of Fig. lor at a different printing "ridges 62' at its lateral edges. The boundary printing lines 63 are helpful in the calibration and use of the apparatus. 'These lines are so spaced with respect to the calibration of the instrument as'to'mark the upper and lower limits of satisfactory welding surges and is notenergized for satisfactory welding surges. Theconnection of the signalling circuit to the recording pointer shaft should be through a connection such as a weak spiral which has negligible turning effect on the shaft in any position.

-In.order to avoid trouble with the carbon paper belt 25 and record paper 22, I have found that certain precautions are very desirable. It

i is difflcult to provide a carbon paper or cloth belt 25 of exactly the same length aLboth ends. For example, the belt may be formed by a. sheet of carbon paper of the desired width and length which, when the endsare pasted together, form a belt." In pasting the ends of the sheet together to form a belt, one peripheral side of the belt may be found to be inch longer than the other in spite of care being taken to prevent any such discrepancy. Such a belt when simply placed on parallel rollers such as the rollers 24 and 10 and driven as here contemplated, will not rungtrue but will invariably work endwise towards that end of the belt which is the longest.

Even collars such as collars H shown at the ends ofroller 24 willnot prevent an uneven belt of carbon paper from working endwise and climbing out over such collar. This troublesome difficulty has been overcome by the use of a wrinkle bar I2 having bends l3 beneath the paper belt lateral position or both" and with boundary so long as the records fall between these lines,

as shown for example by the records in-F'ig.

1, the welder is assured that the welding-surges containthe proper amount of'heat energy to give satisfactory welds. v

If the records go lower as at point? 80a or higher as at point 60b than the limits set, it. may be assumed that something is wrong with the power control apparatus or the welding apparatus. and the trouble should be "located -and correctedbefore further welding operations'are made. 1 I L If pointer 2| is ouside the boundarylimits fl near the-ends of such belt where it is fed onto roller 24'. These bends crowd the end edges of the paper belt inward and cause it to wrinkle upslightly just as it passes into platen roller 24 and the belt is made sufliciently loose to permit this without tearing. When the belt passes over roller-:24, the-chart paper 22 is outside and under sufflcient tension to drive the carbon paper belt and to flatten out the wrinkles in and without causing creasing-of the carbon paper. This pressing and driving action of chart 22 on the carbon paper over a limited periphery of roller 24 allows the belt to adjust itself, the wrinkles in the long end of the belt apparently being pressedout-in a forward direction and the wrinkles in the short end of the belt apparently being pressed'out in a retarding direction to the extent necessary to allow an uneven belt to be driven without working "endwise. Actually, the long end of the belt is driven faster than the short end; due to the adjustment allowed incident to the smoothing out of the wrinkles to the extent necessary to compensate for the difference in peripheral length of the belt at its opposite ends.

The chart 22 used is a relatively thin lightweight paper in order that it will be sufficiently transparent to enable the records, which are made on. the under side of the chart, to be clearly-visible therethrough. It is impracticable to drive such a chart with a toothed drum having driving teeth projecting through holes punched along the edges of the chart. The chart driving arrangement used, and which has been referred to generally above as a driving drum 28, requires some further explanation- I Th driving drum 2!! may be constructed as indicated in Fig. 2, having a soft rubber cylindrical driving section H at its center and soft rubber inwardly tapered guiding sections 15 at its two ends. The remainder of this drum is made of reduced diameter and may be made up of metal parts which serve as supporting and spacing parts, but do not enter into driving contact with the paper. Beneath driving drum 28 is another drum made up of a long central part 16 and short end parts 11. These three parts are so supported as-to be freely rotatable independently of each other. Part 15 is pressed in driving contact with section part 14 or drum 28 and the chart is gripped between these two parts and they constitute the main driving elements of the arrangement. End roller parts 11 are slightly smaller in diameter than part 16 and they are in driving contact with the outer cylindrical portions of section guide roller parts 15. The maximum diameter of parts 15 is slightly greater than the diameter oi. cylindrical part 14, but the minimum diameters of these parts are the same. The chart is of a width equal to the distance between the inner ends of parts 15 and is normally driven in a central position with its end edges in line with the inner ends of the parts 15. In case the chart tends to creep towards one side or the other of such central position, the cone-shaped surface of is an immediate tendency for one edge rides on part 15 and there .driven at the same speed.

such edge to be driven faster than the middle of the chart due to the increased diameter of part 15 and the fact that parts H and 15 are This straightens the chart and returns it to a central driving position. This correcting eifect of the cone-shaped roller parts 15 at any instant is in proportion to extent of chart displacement from a central position at the driving drum. Guide collars H maintain the chart properly centered under the recording position and hence such correcting efiects as occur at the driving drum do not displace the record on the chart.

What I claim as new and desire to secure by Letters Patent of the United States is:

In a recording instrument, a pair of rollers for supporting a record sheet and between which such record sheet is gripped to pull the record sheet forward, a motor for driving one of said rollers. said last mentioned roller having an enlarged friction driving portion at its center and inwardly tapered cone-shaped chart straightening friction sections at its ends, the inner ends of said cone-shaped sections having a diameter not greater than and approximately equal to the center driving portion and a spacing approximately equal to the width of the chart. the other roller of said pair having a central diameter such that a chart will be gripped between it and the central driving section of the driving roller and end sections of reduced diameter opposite the cone-shaped end sections or the driving roller, said reduced end sections having a driving contact with the largest parts of the cone sections and being rotatable independently of the central section of the same roller.

THEODORE A. RICH. 

